Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 290812 AFDAKQ Area Forecast Discussion National Weather Service Wakefield VA 412 AM EDT Sat Jul 29 2017 .SYNOPSIS... Low pressure and an associated cold front will slowly track across the area through midday, then push offshore late this afternoon through tonight. High pressure will be slow to build in from the west on Sunday as low pressure lingers off the coast. The high will become centered over the local area Monday into Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Latest analysis indicates sfc low pressure centered from metro Richmond to the northern Neck, with upper low centered across S Central PA. Coverage and intensity of showers and tstms has diminished since late last evening, though some locally heavy showers/storms persist, mainly from the north side of metro Richmond on ENE to the MD eastern shore. Have cancelled the Flash Flood watch for NC as additional rain today will be from spotty showers/tstms. The remainder of the watch (NE portion of the CWA) will remain in effect through today, mainly due to the highs rainfall amounts that occurred over the past 24 hrs (up to ~5" in some areas). Additional rainfall amounts today will avg 0.50" to 1.00" in the watch area and genly less than 0.50" elsewhere. Some locally heavy downpours and gusty winds possible/along with small hail but severe threat is minimal. Do expect the FF watch to be able to be cancelled prior to the evening end time but left as is for now in case areas of rain persist through the late aftn/early evening. Overall trend today will be for a somewhat limited coverage in precip (especially S) this morning, with some redevelopment likely this aftn as the upper low shifts ESE and strong height falls/cold pool aloft increase the instability even as sfc temperatures remain fairly cool under low clouds. Will have PoPs ramping back up to 50-70% most areas this aftn. Highs today have already occurred in some locations, with readings perhaps falling a few degrees on N winds this aftn. Along with widespread cloud cover and additional precipitation, highs today will be very cool for late July (though not quite to record low max values (see climate section). Highs today will range mainly in the low- mid 70s N to the upper 70s/around 80 F in the SE (but aftn readings will only avg in the mid 60s to lower 70s most areas). && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... Remaining breezy/windy tonight along the coast, and will maintain high chc to likely PoPs early on, then diminishing to 20-30% near the coast after midnight. Becoming partly cloudy to mostly clear overnight west of I-95, remaining mostly cloudy farther E. Lows tonight/Sun am 55-60 F along/west of I-95 and in the 60s farther east except locally around 70 F immediate coast for places such as ORF and NC Outer Banks with strong N/NE winds off the warm waters. For Sun/Mon, models in good overall agreement that sfc high pressure centered over the midwest on Sunday, builds ESE into the local area by monday. Increasing amounts of sunshine will allow temperatures to moderate Sunday with highs in the upper 70s along the coast and in the lower 80s inland (still running 5-10 degrees cooler than avg). Pleasant/dry with aftn dew pts in the 50s most areas Sun/Mon. Mostly clear Sun night with lows mainly in the 50s/around 60 F inland and in the 60s along the coast. Mostly sunny Monday with highs in the upper 70s/lower 80s near the coast and in the mid 80s inland. && .LONG TERM /TUESDAY THROUGH FRIDAY/... High pressure locates over the Mid- Atlantic Tuesday and slides offshore Tuesday night as a cold front drops over the Great Lakes. Dry and still fairly comfortable for Tue as highs begin to moderate to the mid-upper 80s (but dew pts still mainly 60-65 F). Temperatures and dewpoints moderate Wednesday thanks to return flow. More seasonable highs expected Wednesday, generally in the upper 80`s to low 90`s. The cold front progged to reach the Ohio Valley, sharpening the lee/thermal trough over the Piedmont. Moisture return results in slight chance PoPs northwest Thursday for diurnally driven showers/thunderstorms. Highs Thursday again in the upper 80`s to low 90`s. Medium range guidance begins to lift the coastal front northward Thursday night and Friday as an upper level trough digs over the Ohio Valley. The cold front approaches from the northwest. Have slight chance to low end chance PoPs for Friday based on the latest model consensus. Seasonable highs again, generally in the upper 80`s to low 90`s. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... Showers and thunderstorms ongoing across the region with 06Z TAF issuance, with brief IFR conditions in the heavier rain. After 09Z/10Z, a more widespread IFR Cig is likely for RIC/SBY, with MVFR cigs developing ORF/PHF (may remain VFR at ECG). Ceilings will be mainly MVFR after 15Z today, though may see them flirt with IFR at ORF/SBY later in the aftn as stronger N/NE wind develops off the ocean. Also, showers/isolated tstms will tend to be limited in coverage from 12-16Z, then redevelop and become more widespread again during the aftn/early evening (brief IFR vsbys possible in heavier showers). Improving conditions tonight, becoming MVFR to VFR as clouds scatter out. It will be windy along the coast however with N/NE gusts to 25-30 kt most likely at ORF (and 20-25 kt SBY/PHF/ECG). Genly a quiet pattern from Sunday through midweek as high pressure builds in from the WNW and settles across the area Mon/Tue leading to VFR conditions. && .MARINE... Sfc low pressure centered over the middle Ches Bay/lower MD Eastern Shore early this morning will push east and off the Delmarva coast by this afternoon while at the same time dragging its attendant cold front through the local marine area. Already seeing SW winds 20-25 kt up near Tangier this morning with N-NE winds 20-30 kt across the upper Ches Bay and upper Potomac River near the low center. As the low heads east this morning will see winds turn to the N-NE and increase across the northern marine zones...and eventually do the same across the southern marine zones this afternoon. Went ahead and began the Gale Warnings north of Cape Charles as now inside of 12 hrs before gale conditions expected. Did the same for the all SCA headlines (save the Currituck Sound and NC waters where not expecting SCA conditions until this evening). Expecting wind gusts to peak between 25-30 kt most waters, except gusts up to 35-40 kt north of Cape Charles where Gale Warnings are in effect. Seas will quickly build across the north this afternoon, reaching 5-9 ft by this evening. Seas expected to build to 5-8 ft across the south late tonight. The low gradually pulls away from the coast tonight into Sunday with winds slowly subsiding through Sunday. Have the Gale Warning for the northern coastal waters ending at 6 am Sun to be replaced by an SCA at that time. All other SCAs will continue into Sunday aftn/eve. Should be able to end the SCAs for the Rivers/Bay/Sound by Sun eve. However, SCAs for the coastal waters will continue Sunday night and probably into Monday as NE flow keeps seas elevated. Conditions improve by midweek. && .TIDES/COASTAL FLOODING... Moderate rip current risk across the north today with increasing NE flow. Of bigger concern will be the building seas which will produce dangerous surf conditions along the Eastern Shore this afternoon. Will have low rip current risk south due to offshore winds. Hazardous surf conditions expected on Sunday all beaches due to breaking waves of 4-7 ft. Don`t think we quite get to High Surf Advisory criteria (8+ ft). Some minor flooding issues are possible Sunday/Mon along the coast and in the lower Bay with the strong N/NE flow behind the departing sfc low and associated cold front. && .CLIMATE... RER was sent for SBY for daily precip record Fri 7/28 of 3.84". Otherwise, quite cool today, but midnight (EST) temperatures were warmer than the record low max values at all of our climate sites (so no chance on setting any records even if temperatures drop this aftn). For reference, record low max values for today (7/29) are listed below: * Record Low Max Today (7/29) * Richmond: 70 (2001) * Norfolk: 71 (1984) * Salisbury: 66 (2001) * Elizabeth City: 75 (1984) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...Flash Flood Watch through this evening for MDZ021>025. NC...None. VA...Flash Flood Watch through this evening for VAZ064-075>078- 084>086-099-517>522. MARINE...Gale Warning until 6 AM EDT Sunday for ANZ650-652-654. Small Craft Advisory until midnight EDT Sunday night for ANZ656. Small Craft Advisory from 7 PM this evening to midnight EDT Sunday night for ANZ633-658. Small Craft Advisory until 4 PM EDT Sunday for ANZ630-635-636. Small Craft Advisory until 6 PM EDT Sunday for ANZ631-632-637- 638. Small Craft Advisory until 10 PM EDT Sunday for ANZ634. && $$ SYNOPSIS...LKB NEAR TERM...LKB/MAS SHORT TERM...LKB/MAS LONG TERM...SAM AVIATION...LKB/MRD MARINE...JDM TIDES/COASTAL FLOODING... CLIMATE...

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